Crane Cams Dyno - Big, Bigger, Biggest!

Nothing defines the personality of a performance engine quite like the camshaft. From the power to the operating range, and even the curbside bark at idle, the cam sets the tone. With the appropriate cast of supporting components, including the heads, induction, and compression, you can generally expect more peak power as the camshaft is stepped up. On the flip side, those long-duration numbers loathe low-rpm operation, snuffing idle vacuum and driveability. Here lies the classic trade-off in a dual-purpose performance machine—determining how much cam is enough and how much is too much. If your plans are easy street cruising in choked urban traffic, that line is quickly crossed. Contrarily, if max high rpm power with a lumpy boulevard idle announcing your presence is the aim, more cam is usually the word.

The Test

To get a handle on how this all plays out in a real-world engine combination we decided to hit the dyno with three hydraulic roller grinds from Crane Cams. Our test engine is nothing more exotic than a production big-block Chevy 454. The engine was prepped by boring it out for a set of short-dome JE pistons to bring the compression ratio over the 10:1 mark, adding a set of Scat H-beam rods for durability, while freshening the stock Chevy crank. Up top, we went with a set of deceptively capable oval-port AFR cylinder heads. The heads feature a modest port volume of just 265 cc, but these fully CNC-ported castings have the airflow to support healthy output. Supplying the air is an Edelbrock Performer RPM Air-Gap intake manifold fed by a Holley 950 Ultra HP 4150-series carburetor. In short, our engine is the type of budget performance Chevy big-block you’ll find on streets across the United States, based on production components and spiced up with aftermarket goodness where it counts.

With the popularity of hydraulic roller cams in today’s street builds, it made sense to select that cam configuration for our dyno session. The advantages of the juice roller include virtually eliminating unexpected cam lobe/lifter failure in initial running, and the ability to add enough valvespring reliably to spin up some high-rpm power. The roller profiles offer much more lift than we would expect to run reliably on a flat-tappet combination, giving the potential for serious power production. To complement the cam, we opted for a set of Crane’s standard retrofit hydraulic roller lifters, PN 13532-16, along with Crane’s excellent 13763TR-16 aluminum-bodied roller rocker arms. The cylinder heads were ordered with AFR’s excellent hydraulic roller spring combination, so we were covered there.

Cammed For Power

To best illustrate the varied characteristics affected by cam size, it made sense to step the specifications up fairly substantially between the cams. We opted for sizable jumps of 12 and 14 degrees duration as measured at .050-inch lift. Our baseline cam, with 222/230 degrees duration at .050 would be considered a baby cam by performance veterans, but with lift of .576/.598 inch, it moves the valves with authority, and with a healthy lope can in no way be construed as a stock cam. Testing showed that even this small stick has its big-boy pants on, taking our mild 454 combo up to 570 hp at 5,800 rpm, and pulling cleanly over 6,200 rpm.

That’s healthy power for a pump-gas street 454. What was more impressive came lower in the operating range, where the torque right off the hit at 3,000 rpm was 539 lb-ft, twisting strongly to a peak of 587 lb-ft from 3,900 to 4,100 rpm. Our small cam delivered the torque needed to launch heavy street metal, while dishing plenty of punch up top. While the duration specs would seem conservative, don’t be fooled, this unit definitely proved to be performance minded. The smallest of our trio of cams idled with a noticeable performance lope and registered a healthy 15 in-hg of vacuum at a 1,000-rpm idle.

Our next step in cam size moved up to 234/242 degrees duration at .050, a neighborhood that is popular with today’s street performance enthusiasts. We tore the engine down as it sat on the dyno for the cam change, retaining everything else exactly as it was in our previous combination. The upsized cam featured a significant jump in lift, shoving the valves to well over the .600-inch mark. We expected the increase in lift and duration to tap into more of the excellent high-lift airflow of the AFR heads, and bump top end power. The dyno numbers showed a textbook example of what is gained and what is lost as the cam timing is increased. Up top, we now recorded 599 hp at 6,100 rpm, gaining in both output and usable rpm, however, the bump of 12 hp up top shaved 8 lb-ft from peak torque, and shifted the torque peak higher up the rev range. This move in the torque curve was most noticeable in the lower end of the rev range, with substantial torque losses below 4,000 rpm. Idle lope was noticeably more pronounced and vacuum measured 12 in-hg at 1,000 rpm.

Here lies the classic trade-off in a dual-purpose performance machine —determining how much cam is enough and how much is too much.

More Manifold & Cam

…even this small stick has its big-boy pants on, taking our mild 454 combo up to 570 hp at 5,800 rpm…

Our intermediate cam was clearly favoring the upper end of the rpm range, and at this level of cam duration a single-plane intake manifold would likely further complement the high-rpm power. To explore the effects of a change in manifold configuration, we swapped the intake to Edelbrock’s Victor Jr. 454-O, a single-plane designed for the oval-port heads. With no other changes to our test engine, the swap resulted in a classic example of a single-plane versus dual-plane comparison. Up top, we now recorded 609 hp from 6,000-6,200 rpm. With handily over 600 hp on tap, we definitely gained in bragging rights, but it came with a clear loss in torque at lower rpm. The point at which peak torque occurred moved up and moved peak torque rpm up by a surprising 900 rpm. The single-plane runner layout also resulted in a small penalty in idle vacuum, now recorded at 11.7 in-hg at 1,000 rpm.

8/12Our first move up the ladder bumped the intake duration at .050 by 12 degrees with a 234/242-degree stick, and boosted lift to .610/.632 inch. We lubed the cam and installed it with no other changes to the engine combo.

Our final test configuration featured another large move up in camshaft specs, this time to 248/256 degrees duration at .050- and .630-inch lift, retaining the single-plane manifold from our previous test. Our big cam definitely made itself known with a raucous lope and just 7.0 in-hg of vacuum at 1,000 rpm. Following the pattern of our previous tests, the big stick once again traded torque downstairs for horsepower at the upper reaches of the tach. We now had an impressive 630 hp on tap at 6,400 rpm, with the combination pulling cleanly to a maximum of 6,700 rpm. Those numbers are pretty imposing for a pump-gas street 454!

9/12With the “bigger” cam noticeably favoring the top end of the power curve, this level suggested a single-plane intake might further help peak output. We swapped to the Edelbrock Victor Jr. 454-O and saw an even 10 hp gain up top.

The penalty here, as you might expect, is more torque skinned off the lower rpm range. Compared to our baseline combo we were down over 80 lb-ft at 3,000 rpm, although looking at torque from peak to peak the difference shrinks to just 10 lb-ft. As had been the case through each of our changes, the powerband moved up, trading bottom end output and idle quality for more all-out power. These compromises are the essence of what performance enthusiasts are faced with when making their camshaft decision. Our baseline cam delivered mountains of low-end grunt, and has the legs for excellent power up top. The ferocious idle of our big cam would definitely come with compromises in street driveability, but might just offer the boulevard presence and power curve you are after. With a serious converter and street tires, the torque lost down low would likely never even make itself known. When it comes to cams, one size doesn’t fit all, the right cam is tailored to your application and goals.

10/12The “bigger” intermediate cam exhibited exactly the change to the engine’s characteristics one might expect, increasing output up to just shy of 600 hp, while taking torque numbers off the bottom of the rev range. Idle vacuum dropped from 15 to 12 in-hg.

11/12With our final cam change our 454 was carrying a big stick, with duration at .050 now at 248/256, and lift at .632/.632 inch. The big cam sounded off with the characteristic window-rattling lope, while extracting 630 hp from our pump-gas big-block.

12/12Illustrated graphically, it is clear how each larger cam stepped up the top end power but sliced ever larger chunks from the low-end torque. Is the trade worth it? The answer is as individual as your own objectives from your engine.

On The Dyno
Crane Hydraulic Roller Cams
454ci Big-Block Chevy

TQ:

HP:

RPM:

222DP

234DP

234SP

248SP

222DP

234DP

234SP

248SP

3,000

539

508

487

457

308

290

278

261

3,100

539

508

487

457

318

300

287

270

3,200

542

513

491

462

330

313

299

282

3,300

549

523

501

474

345

329

315

298

3,400

558

535

512

488

361

347

332

316

3,500

567

547

521

500

378

365

347

333

3,600

575

557

528

508

394

382

362

348

3,700

581

564

533

516

409

397

376

363

3,800

585

569

539

524

423

412

390

379

3,900

587

573

543

532

436

426

403

395

4,000

587

576

547

538

447

439

416

410

4,100

587

578

552

545

458

452

431

426

4,200

585

580

558

554

468

464

446

443

4,300

583

580

563

564

477

475

461

461

4,400

580

579

567

570

485

485

475

478

4,500

576

577

569

574

493

495

488

492

4,600

572

575

571

576

501

504

500

505

4,700

567

572

572

577

508

512

512

516

4,800

563

570

574

577

515

521

524

528

4,900

559

568

574

577

522

529

536

538

5,000

555

565

575

577

528

538

547

549

5,100

552

563

575

577

536

546

558

560

5,200

549

559

574

577

543

554

568

572

5,300

545

556

572

577

550

561

578

582

5,400

541

552

569

576

556

567

586

592

5,500

536

548

566

573

561

574

592

600

5,600

530

544

561

569

566

581

598

607

5,700

524

541

555

565

569

587

602

613

5,800

516

537

549

559

570

593

606

617

5,900

507

531

542

552

569

597

608

620

6,000

497

524

534

546

568

598

609

624

6,100

485

516

524

538

563

599

609

625

6,200

470

505

516

530

555

597

609

626

6,300

524

628

6,400

517

630

6,500

509

629

6,600

500

628

6,700

491

627

By The Numbers
Crane Cam Specifications

Crane grind number:

Duration at .004 inch:

Duration at .050 inch:

Lift:

LSA:

HR 222/239-2S-10

284/292 degrees

222/230 degrees

0.576/0.598 inch

110 degrees

ZHR-296-2S-12

296/304 degrees

234/242 degrees

0.610/0.632 inch

112 degrees

HR-248/372-2S-10

310/318 degrees

248/256 degrees

0.632/0.632 inch

110 degrees

See More Online

We captured our three-cam, two-intake dyno test on video, so if you want more, log on to our Video page at PopularHotRodding.com!